tire pressure?

Dwight · #1 (**permalink**) 08-05-2018, 07:19 PM

I have 315/35ZR17 on the rear and 225/40ZR17 on the rear. Car should weight about 2300-2400 lbs plus fuel and driver.

What tire pressure should I run?

bobcowan · #2 (**permalink**) 08-05-2018, 08:25 PM

A good place to start is 1 psi for every 100 pounds. So start at 25. Use tire tread temps to find the exact right answer.

Ron61 · #3 (**permalink**) 08-06-2018, 04:16 AM

On my Coupe I normally run around 28 pounds. In cooler weather I may bump it up to 30.

Ron

Dwight · #4 (**permalink**) 08-06-2018, 06:35 PM

I put 28 lbs in today.

Trying to crank the motor for the first time. My buddy is going to bring his laptop over and we'll see what on the ECU.
When I try to crank it I have no spark and no fuel pass the injectors.

Maybe a wire installed incorrectly. I just download all the programs on a flash drive for his laptop.
After we get it crank then it's off to the dyno for tuning and then the paint shop.
That is why I'm checking the tire pressure.

TexasSnake · #5 (**permalink**) 08-07-2018, 02:56 PM

Dwight,

I have a FE powered B&B setup with 17 inch American Racing Vintage 427 wheels and Nitto 555 Extremes. 17x8 wheels with 245/45/17 front rubber and 11x17 wheels with 315/35/17 rubber in the rear. I run 24 PSI cold front and rear with really good results. Hope this helps you out.

Dwight · #6 (**permalink**) 08-07-2018, 09:01 PM

Thanks

Howard Jones · #7 (**permalink**) 10-06-2018, 01:45 PM

I have about 25000 miles on my GTD. About half are track miles. Here's my tire pressure data for front 243.40.17 and rear 315.35.17.

I have camber set at F -.75 degrees, R -.5 degrees, Toe at 1/8" total front and 1/16" total rear.

On hot days at track >90-95F air temp start fronts at 26psi and rears at 25psi. Tires can be expected to pump up 3-5 psi. I think the cars feels best at 28 both. The cars goes to oversteer or understeer if pressure goes over 30psi at either end.

Under 80F air temp start tires +1 psi front and +2 psi rear with same pumped up target of 28psi.

Check after each run and adjust back to 28psi both.

Street cruse: tires will still pump up somewhat on a hot summer day but more like 1-2 psi over a couple of hours. If you are only going out in the morning for a hour or two start at 28 and it will be OK. Very hot days maybe try F-27 R-28.

As you can see when a lot of power is being used then the rear will pump up quite a bit whereas the fronts will pump up just a bit more when straight line highway drives over a few hours are on the agenda.

I have put both Continentals and Sumitomo summer only tires on this car and both seamed to like the same pressure.

Good luck with your new car and check those tire pressure a lot until you find what you like. You will be safe down to 24-25 psi but edge wear will go up at low pressures.

Dwight · #8 (**permalink**) 10-07-2018, 08:02 AM

Thanks Howard
that is information I'm looking for.

Dwight

Bruce.huling · #9 (**permalink**) 05-07-2021, 06:13 PM

Quote:

Originally Posted by TexasSnake

Dwight,

I have a FE powered B&B setup with 17 inch American Racing Vintage 427 wheels and Nitto 555 Extremes. 17x8 wheels with 245/45/17 front rubber and 11x17 wheels with 315/35/17 rubber in the rear. I run 24 PSI cold front and rear with really good results. Hope this helps you out.

I have same tires, so thank you for sharing your experience